Systems for pasteurizing liquids, e.g., raw milk, are widely used through the world. Such systems help assure that milk suitable for human consumption, sold as "Grade A" milk in the United States, has been processed in a particular way to achieve pasteurization. The Milk Safety Branch of the U.S. Food and Drug Administration (FDA) has established standards governing the construction and operation of such systems. Such standards are extremely strict and well enforced by a network of regulatory officials. In fact, most milk producers are well aware of the problems that might arise from selling tainted milk and carefully adhere to such standards in operating pasteurizing systems.
That such standards are highly effective in protecting the public health is evidenced by the fact that at least in the U.S., milk-borne diseases are all but unknown. And other milk-producing countries recognize the efficacy of the FDA standards to such an extent that they have become de facto international standards widely adhered to outside the U.S.
Modern pasteurizing systems are of the type known as high temperature short time (HTST) systems. In such systems, the product being pasteurized, e.g., milk, is maintained at the relatively high temperature of about 162.degree. F. for a minimum of about 16-17 seconds. Milk which has been subjected to such process is known as pasteurized milk.
Such pasteurizing systems may be broadly divided into two portions, namely, handling and treating equipment and pasteurizing control apparatus. The former includes among other components, holding tanks and piping which flow milk to heating devices where pasteurization occurs. The latter includes a flow diversion valve which receives milk from the handling and treating equipment. Under certain predetermined, precisely-defined circumstances which evidence that pasteurization has occurred, such flow diversion valve is controlled to direct milk into a receiving tank for later placement into containers for sale. If pasteurization has not occurred of if, for example, pasteurized milk is to be drawn off for inspection rather than sale, the flow diversion valve is controlled to direct milk through piping other than that to the receiving tank, for example, if pasteurization has not occurred, milk is usually "recycled" back into a tank for re-processing.
The importance of a properly-controlled flow diversion valve means cannot be overstated. That is, the integrity of the valve controller is a fundamental determinant as to whether the milk sold to the public is pasteurized. In fact, controllers used with such flow diversion valves are often called "public health controls" for obvious reasons.
While the flow diversion valve is important (as is proper operation thereof), a typical system for processing a food product such as milk has a number of other components which must be controlled or at least selected for the system to work properly. For example, there may be one or plural tanks for holding raw milk awaiting pasteurization, a constant level tank, pumps, a homogenizer, a heat exchanger, a cooler and more or plural tanks for holding the milk pasteurized by the system and awaiting containerization. One of plural holding tanks and/or one of plural pasteurized milk tanks has to be selected and all of these components are connected together by pipes to form the pasteurizing system.
Until the advent of the invention, only the flow diversion valve was coupled to any kind of an apparatus which could provide automatic control. Such a control apparatus for a flow diversion valve is the subject of U.S. Pat. No. 5,054,385 (Scheel et al.) which is assigned to the assignee of the instant invention.
And until the advent of the invention, the system components other than the flow diversion valve were controlled by diverse devices, the operations of which were cooperatively "integrated" only by the ingenuity and know-how of the people (usually dairy personnel) operating them. The fact that milk-borne diseases are all but unknown in the United States is a tribute to the capabilities of such personnel and to the reliability of the system components.
But there are disadvantages to the apparatus used to operate such systems. For example, when "setting up" a system to pasteurize a product, there are a substantial number of choices to be made by the operator. S/he must select the desired tanks (if the system has plural tanks of either type) and also select such things as system operating mode (e.g., recycle, drain, discharge), batch size, the product to be processed (e.g., yogurt liquid, whole milk, 1/2% milk) and heat exchanger water temperature. Pumps to flow milk through the system must also be actuated.
And that is not all. Pasteurizing systems are often arranged to be "cleaned in place." A clean-in-place (CIP) operation involves purging the system of milk product and flowing very hot water through the system to sterilize it. CIP operation presents yet additional choices to be made by the operator. The array of choices can be baffling and mistakes during system setup and process initiation are not unheard of. Existing control apparatus simply does not organize and is incapable of organizing the setup tasks in a highly coherent way.
Still another disadvantage of known control apparatus is that there is no convenient means for report generation. It is highly desirable to keep records on a number of aspects of the pasteurizing process and the product resulting therefrom. Typically, such records are created manually and are subject to error, perhaps even falsification.
Yet another disadvantage of known control apparatus (as well as of the pasteurizing systems controlled by them) relates to the production of milk or milk products having reduced butterfat content. Since many of the vitamins in milk are present in the butterfat, the removal of such butterfat (to make skim milk, for example) also removes vitamins. Such vitamins are required to be added back in to the final product and milk with vitamins added is said to be "fortified." Current "technology" for fortifying milk is by a container (e.g., a pail) of vitamin solution poured into the appropriate tank. The mixing ratio is less than precise.
An improved apparatus and method which addresses the aforementioned disadvantages would be an important advance in the art.